1. Field of the Invention
The present invention relates to a display apparatus and a method for driving the same, and more particularly to a technique for reducing noise that a display apparatus such as a plasma display panel emits.
2. Description of the Related Art
Recently, a variety of display apparatuses have been researched and developed, and among them, plasma display panels (PDPS) and liquid crystal displays (LCDs) have been commercially implemented as flat display apparatuses having excellent display quality.
In these display apparatuses, the display panel is driven by a drive waveform generated in accordance with a fixed-frequency clock, and since the display panel is exposed to the outside, noise emission becomes a problem. To reduce noise below a specified level, it is practiced to adjust the shape of the display panel driving waveform (rise/fall shapes) or to provide a shield structure by attaching a conductive transparent film to the display panel. However, these techniques involve problems in terms of stable operation of the display apparatus and the cost of the apparatus, and drastic measures for solution are needed.
For example a clock circuit of a prior art plasma display apparatus is configured as a fixed-type clock oscillator. Generally, when an electronic apparatus operates, electromagnetic waves propagate through a medium such as space or electric wire as the current and voltage vary. In the case of a plasma display apparatus, these include visible light rays produced as the display light, and near infrared rays, magnetic field waves, electric field waves, etc. are emitted depending on differences in wavelength. In this case, all components other than the visible light rays intended for the operation of the apparatus can be defined as noise.
These components (noise), depending on their wavelength and strength, can cause malfunctioning or failure of other apparatuses located nearby, if this situation were left unaddressed, a valid environment for electronic apparatuses could not be provided. Therefore, in each country of the world, upper limits of noise that electronic apparatuses are permitted to emit are specified by law, self-imposed restrictions among manufactures, etc., and products conforming to the law, self-imposed restrictions, etc. by reducing noise using various means are distributed in the market.
The prior art and the problems associated with the prior art will be described in detail later with reference to accompanying drawings.